But that's not hard enough. They need more cowbell, according to Defense Secretary Leon Panetta. While the bomb—which is designed to be delivered using B-2 stealth bombers—can seriously damage Iran's underground nuclear facilities, it wouldn't completely destroy them. He said that they are still developing it:

I think we're pretty close, let's put it that way. But we're still working at it because these things are not easy to be able to make sure that they will do what we want them to. But I'm confident, frankly, that we're going to have that capability and have it soon.